Roger Boisjoly had over a quarter-century's experience in the aerospace industry in 1985 when he became involved in an improvement effort on the O-rings which connect segments of Morton Thiokol's Solid Rocket Booster, used to bring the Space Shuttle into orbit. Boisjoly has spent his entire career making well-informed decisions based on his understanding of and belief in a professional engineer's rights and responsibilities. For his honesty and integrity leading up to and directly following the shuttle disaster, Roger Boisjoly was awarded the Prize for Scientific Freedom and Responsibility by...
Roger Boisjoly had over a quarter-century's experience in the aerospace industry in 1985 when he became involved in an improvement effort on the O-rings which connect segments of Morton Thiokol's Solid Rocket Booster, used to bring the Space Shuttle into orbit. Boisjoly has spent his entire career making well-informed decisions based on his understanding of and belief in a professional engineer's rights and responsibilities. For his honesty and integrity leading up to and directly following the shuttle disaster, Roger Boisjoly was awarded the Prize for Scientific Freedom and Responsibility by the American Association for the Advancement of Science.
Mr. Boisjoly died of cancer in St. George, Utah on Jan. 6, 2012. He spent his final years offering workshops and lectures on changing workplace ethics for numerous universities and civic groups.
For more information see this rememberance on NPR.
January 28, 1986. Two video clips of the Challenger Explosion from CNN: "Reagan honors shuttle crew (1986)" and "NASA remembers Challenger".
In January of 1987, nearly a full year after the Challenger exploded, Roger Boisjoly spoke at MIT about his attempts to avert the disaster during the year preceding the Challenger launch. According to the Report of the Presidential Commission on the Space Shuttle Challenger Accident, "evidence pointed to the right solid rocket booster as the source of the accident." In 1985 Boisjoly began work to improve the O-ring seals which connect segments of Morton Thiokol's solid rocket booster. Boisjoly was frustrated with the slow progress and the lack of management attention to the seal task force. He spoke about the events leading up to the disaster in this address.
Boisjoly's discussion of the Challenger Disaster is separated into seven sections. Each section is then followed by some possible responses. To see discussion of any response, click on the link to it. Supporting material is also provided. You may want to consult some of it in deciding what you would have done in Roger Boisjoly's place at each stage of the story.
This page and supporting pages were originally created by Jagruti S. Patel and Phil Sarin.
Roger Boisjoly presented this material first in a talk in January 1987 at MIT. The first publication was in the volume of conference papers for the 1987 Annual Meetings of the American Society of Mechanical Engineers in fall 1987.
Boisjoly, Roger M. 1987.
Ethical Decisions -- Morton Thiokol and the Space Shuttle Challenger Disaster.
American Society of Mechanical Engineers Annual Meetings.
Why was Roger Boisjoly so concerned about O-Rings? These
seemingly insignificant pieces of rubber played a critical role
in the joints between segments of a solid rocket boster
The two SRBs attached to a space shuttle orbiter provided
eighty percent of the thrust necessary to propel the shuttle
into space. About two minutes after a normal launch, the SRBs
would detach and parachute back to the ground to be reused in
subsequent missions. Several cylindrical segments make up the
149.1-foot- (45.4-meter-) tall SRB. Each joint between these
segments contains two O-rings, positioned concentric with the
SRB. The O-rings must be in perfect condition to prevent hot
gasses from leaking through the joints of the SRB.
Within a second of the launch of Challenger on January 28,
1986, the first signs of failure of a joint in the right SRB
were visible. Puffs of black smoke, whose color suggested that
5800-degree gases were eroding the O-rings, spewed out of that
joint three to four times each second. At the end of the first
minute, a small but steady flame was evident.
Atmospheric and aerodynamic conditions directed the flame
plume onto the surface of the External Tank, used to supply liquid
hydrogen and liquid oxygen fuel to the shuttle's engines during
the launch. The flame eventually breached the tank, and a
massive amount of hydrogen and oxygen burst into flame. At 73
seconds, a nearly explosive burn of the hydrogen and oxygen
quickly resulted and claimed the Challenger with its crew.
Above: A Solid Rocket Booster and its segments. The aft
field joint (arrow) failed in the Challenger's right SRB.
A Solid Rocket Motor Joint. Its parts are colorized in this
diagram for clarity. In pink is the tang,
which joins the clevis, colored orange. 177
huge steel pins (yellow) hold the joint in place. The O-rings
shield the joint from 5800-degree gases inside the booster.
On the left scenario, hot gases (red arrows) are shielded
from the joint by the zinc-chromate putty. On the right,
immense pressure creates a blowhole in the putty, allowing the
O-rings to move into the positions needed to seal the joint as
the gap between tang and clevis expands. Through the blowhole,
gases penetrate and wear away the O-rings.
Boisjoly had noticed that O-rings eroded, to an extent, in
this fashion previously. NASA and Thiokol, however, decided
that, since the O-rings were not completely eroded, there was
minimal risk. Boisjoly's concern was that the low launch
temperature would cause the O-rings to contract and further
compromise their sealing value.
This diagram is a cross section. In actuality, the joint
itself, tang, clevis, and O-rings have the circular shape of
Sources:Report to the President by
the Presidential Commission on the Space Shuttle Challenger
Photographs adapted from pages 112, 52, and 57 of the
Presidential Commission Report.